The present invention relates to current limiting devices for electrical power systems.
In electric power systems, generation, transmission and distribution equipment must be protected from overloads due to currents above safe levels. Such protection is normally provided by circuit breaker devices comprising electrical contacts and means for actuating the contacts upon detection of excessive current. Conventional circuit breaker devices, however, have limitations on the fault current they can interrupt. Hence in many applications, fault current limiting is needed so as not to exceed the ratings of breakers.
Other types of current limiting devices have been proposed. Among these are nonlinear resistance devices utilizing pressurized mercury and conductive ceramics. These devices have not, however, been adopted into general use.
Accordingly, there remains a need for an improved current limiting device for use with or in lieu of circuit breakers in electric power systems.